Submission #488384

#	Time	Username	Problem	Language	Result	Execution time	Memory
488384		SlavicG	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	307 ms	344052 KiB

shoes

#include "bits/stdc++.h"
using namespace std;
 
#define ll long long
 
#define       forn(i,n)              for(int i=0;i<n;i++)
#define          all(v)              v.begin(), v.end()
#define         rall(v)              v.rbegin(),v.rend()
 
#define            pb                push_back
#define          sz(a)               (int)a.size()

const int N = 5e5 + 10;
ll fen[N];

void modif(int u){
    for(int i = u + 1;i < N; i += (i & (-i))){
        ++fen[i];
    }
}

ll query(int l, int r){
    ll ret = 0;

    for(int i = r + 1;i > 0; i -= i &(-i)){
        ret += fen[i];
    }
    for(int i = l;i > 0;i -= i & (-i)){
        ret -= fen[i];
    }

    return ret;
}

ll count_swaps(vector<int> s){
    int n = sz(s) / 2, m = sz(s);
        
    for(int i = 0;i < N; ++i)fen[i] = 0;
    vector<bool> done(m + 5, 0);
    int cnt = 1;

    queue<int> q[N];

    vector<int> a(m, -1);
    for(int i = 0;i < m; ++i){
        q[s[i] + n].push(i);
    }
    for(int i = 0;i < m; ++i){
        if(done[i])continue;

        if(s[i] > 0){
            a[i] = cnt + 1;
            done[i] = true;

            a[q[n - s[i]].front()] = cnt;
            done[q[n - s[i]].front()] = true;

            q[s[i] + n].pop();
            q[n - s[i]].pop();

            cnt += 2;
        }else{
            a[i] = cnt;
            done[i] = true;

            a[q[n - s[i]].front()] = cnt + 1;
            done[q[n - s[i]].front()] = true;

            q[s[i] + n].pop();
            q[n - s[i]].pop();

            cnt += 2;
        }
    }

    ll ans = 0;
    for(int i = 0;i < m; ++i){
        ans += query(a[i] + 1, m + 5);
        modif(a[i]);
    }

    return ans;
}

/*
void solve()
{ 
    int n;
    cin >> n;
    vector<int> a(n);
    for(int i = 0;i < n; ++i){
        cin >> a[i];
    }

    cout << count_swaps(a) << "\n";

}   
 
int32_t main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int t = 1;
    //cin >> t;
    while(t--)
    {
        solve();
    }
}
*/

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 15 / 15